JavaCTAPL的NoClassDefFoundError
我正在尝试编写一个程序,该程序将利用树API(请参阅)。基本思想是创建一个,并使用它来获得一个。返回的JavaCTAPL的NoClassDefFoundError,java,Java,我正在尝试编写一个程序,该程序将利用树API(请参阅)。基本思想是创建一个,并使用它来获得一个。返回的CompilationTask实际上是javactasquimpl的一个实例(请参见下面的代码)。但是当我尝试将返回的编译任务强制转换为javactasquimpl时,我得到了一个NoClassDefFoundError import javax.tools.JavaCompiler; import javax.tools.JavaCompiler.CompilationTask; import
CompilationTask
实际上是javactasquimpl
的一个实例(请参见下面的代码)。但是当我尝试将返回的编译任务
强制转换为javactasquimpl
时,我得到了一个NoClassDefFoundError
import javax.tools.JavaCompiler;
import javax.tools.JavaCompiler.CompilationTask;
import javax.tools.JavaFileObject;
import javax.tools.StandardJavaFileManager;
import javax.tools.ToolProvider;
import com.sun.tools.javac.api.JavacTaskImpl;
public class Main {
public static void main(String[] args) {
JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
StandardJavaFileManager fileManager = compiler.getStandardFileManager(null, null, null);
Iterable<? extends JavaFileObject> fileObjects = fileManager.getJavaFileObjects("Test.java");
CompilationTask task = compiler.getTask(null, fileManager, null, null, null, fileObjects);
// Prove that this is indeed an instance of JavacTaskImpl.
System.out.println("Task.getClass(): " + task.getClass());
JavacTaskImpl javacTask = (JavacTaskImpl) task;
}
}
但是使用
$JAVA_HOME/bin/java Main -cp $JAVA_HOME/lib/tools.jar
生成以下输出:
Task.getClass(): class com.sun.tools.javac.api.JavacTaskImpl
Exception in thread "main" java.lang.NoClassDefFoundError: com/sun/tools/javac/api/JavacTaskImpl
at Main.main(Main.java:19)
Caused by: java.lang.ClassNotFoundException: com.sun.tools.javac.api.JavacTaskImpl
at java.net.URLClassLoader$1.run(URLClassLoader.java:217)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
at java.lang.ClassLoader.loadClass(ClassLoader.java:321)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294)
at java.lang.ClassLoader.loadClass(ClassLoader.java:266)
... 1 more
如何消除此错误?您必须在
JavaCompiler.getTask
中设置选项(请参阅)。最简单的方法是使用系统属性:
import com.sun.tools.javac.api.JavacTaskImpl;
import java.util.Arrays;
import javax.tools.JavaCompiler;
import javax.tools.JavaCompiler.CompilationTask;
import javax.tools.JavaFileObject;
import javax.tools.StandardJavaFileManager;
import javax.tools.ToolProvider;
public class Main {
public static void main(String[] args) {
JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
StandardJavaFileManager fileManager = compiler.getStandardFileManager(null, null, null);
Iterable<? extends JavaFileObject> fileObjects = fileManager.getJavaFileObjects("Test.java");
String classPath = System.getProperty("java.class.path");
CompilationTask task = compiler.getTask(null, fileManager, null,
Arrays.asList("-classpath", classPath),
null, fileObjects);
// Prove that this is indeed an instance of JavacTaskImpl.
System.out.println("Task.getClass(): " + task.getClass());
JavacTaskImpl javacTask = (JavacTaskImpl) task;
}
}
import com.sun.tools.javac.api.javactapl;
导入java.util.array;
导入javax.tools.JavaCompiler;
导入javax.tools.JavaCompiler.CompilationTask;
导入javax.tools.JavaFileObject;
导入javax.tools.StandardJavaFileManager;
导入javax.tools.ToolProvider;
公共班机{
公共静态void main(字符串[]args){
JavaCompiler=ToolProvider.getSystemJavaCompiler();
StandardJavaFileManager fileManager=compiler.getStandardFileManager(null,null,null);
可迭代的
import com.sun.tools.javac.api.JavacTaskImpl;
import java.util.Arrays;
import javax.tools.JavaCompiler;
import javax.tools.JavaCompiler.CompilationTask;
import javax.tools.JavaFileObject;
import javax.tools.StandardJavaFileManager;
import javax.tools.ToolProvider;
public class Main {
public static void main(String[] args) {
JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
StandardJavaFileManager fileManager = compiler.getStandardFileManager(null, null, null);
Iterable<? extends JavaFileObject> fileObjects = fileManager.getJavaFileObjects("Test.java");
String classPath = System.getProperty("java.class.path");
CompilationTask task = compiler.getTask(null, fileManager, null,
Arrays.asList("-classpath", classPath),
null, fileObjects);
// Prove that this is indeed an instance of JavacTaskImpl.
System.out.println("Task.getClass(): " + task.getClass());
JavacTaskImpl javacTask = (JavacTaskImpl) task;
}
}